What is quantum biology?

Daniel and Kelly explore how biological systems rely on the quantum nature of matter.

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Episode Transcript

Speaker 1 (00:08):
Hey, Kelly, how do biologists feel about quantum mechanics.

Speaker 2 (00:12):
Well, I don't feel comfortable speaking for all biologists, but
i'd say for myself, I'm mostly uncertain.

Speaker 1 (00:19):
Are you uncertain about whether quantum mechanics makes sense?

Speaker 2 (00:23):
Well, when I was working on my PhD, I did
some work on neurotransmitters and steroid hormones, and all of
that was so complicated and often didn't go as predicted.
It's hard for me to believe that when you go
another step down to the quantum mechanics level, that we
could make any sense of it.

Speaker 1 (00:40):
So are you attempted to just like brush all the
quantum details into the rug?

Speaker 2 (00:43):
Well, I'd be okay with letting physicists worry about the
particles doing their quantum thing, and you'd all worry about
the pests and the parasites.

Speaker 1 (00:52):
That feels like a fair division of labor, unless unless, what,
unless it's actually all entangled and you can never escape
quantum mechanics. Excuse my evil cackle.

Speaker 2 (01:14):
It was a good evil cackle.

Speaker 3 (01:15):
Oh good.

Speaker 2 (01:31):
Hi.

Speaker 1 (01:31):
I'm Daniel. I'm a particle physicist and a professor at
UC Irvine, and I've been practicing my evil quantum wizard Cackle.

Speaker 2 (01:39):
And I'm Kelly Wiener Smith, an adjunct assistant professor at
Rice University. And I've been trying to avoid thinking about
quantum mechanics and animal behavior.

Speaker 1 (01:49):
But is that even possible?

Speaker 2 (01:51):
I guess the answer is definitively no. It's collapsed to
know as of this.

Speaker 1 (01:56):
Conversation, especially if you're a guest host on a physics
pot cast. Kelly, that's not a great way to avoid
quantum mechanics.

Speaker 2 (02:02):
I've made bad choices.

Speaker 1 (02:05):
Well, welcome all of you to the podcast Daniel and
Jorge Explain the Universe, a production of iHeartRadio in which
we marinate in the mysteries of quantum mechanics. We get
down and dirty into the mud of the quantum realm.
We try to understand how this incredible experience that we live,
all the ice cream and the goats and the blueberries

(02:25):
and the blue skies, can somehow be made of these tiny,
frothing quantum particles that behave according to fundamentally different rules
than the ones we experience.

Speaker 2 (02:35):
And we don't even understand the biology rules, but let's
try the physics ones.

Speaker 1 (02:41):
The whole point of reductionism is to say, well, everything
is big and complicated up here. Let's dig down deep.
Let's pull the universe apart and try to understand it
at its tiniest little bits. Maybe down there things will
be simple, will be clear, will be crisp. And from
that understanding, from that firm foundation, maybe we could build
up a comprehension of everything else that flows from that,

(03:03):
including goats and ice cream and parasites.

Speaker 2 (03:06):
Well, I'm not sure I believe.

Speaker 1 (03:08):
It, but we'll find out. It's a big goal. It's
a stretch of goal, let's say, of science. You know,
along the way we hope to learn a few things.
But that's sort of the fantasy, right that we could
understand the universe in terms of its smallest little bits.

Speaker 2 (03:23):
I do think we'll get there. It's going to be
a little bit hard to connect across these levels, but
it's a worthy goal.

Speaker 1 (03:30):
Often in science we do a division of labor. We say, look,
economists can worry about things at a certain level, and
palaeontologists worry about things at another level, and quantum physicists
worry about things at a different level. And often these
levels are distinct. Like when you do fluid mechanics, you
don't really have to understand all the forces between the
little particles, and when you do economics, you don't have

(03:51):
to understand the chemical reactions inside everybody's fingers. You can
like abstract that away, and you can do science at
so many different levels in our universe. It's sort of
an amazing fact, and it's like the reason why we
have anything but quantum mechanics and particle physics.

Speaker 2 (04:06):
And so today you're going to try to convince me
that we can understand animal behavior better by connecting with
our quantum people. Is that right?

Speaker 1 (04:14):
Today we're going to ask if that's really fair. We're
going to ask if there are cracks in that division
of labor, if quantum mechanics is bleeding through Somehow are
there clues in the way we behave and animals behave
and in the biological world that reveal the fundamental quantum
nature of the universe or is it deeply locked behind
these philosophical walls and completely abstracted away.

Speaker 2 (04:37):
It would be so nice if you could go into
your own little cove and you didn't have to look out.
But I'm guessing the answer is going to be you
see more clearly when you see from a variety of
angles m Well.

Speaker 1 (04:48):
Today on the podcast, we'll be asking the question what
is quantum biology? This does sound like the name of
a weird startup, doesn't it.

Speaker 2 (05:01):
Yeah, it does. I hadn't thought of it that way,
but yeah, i'd work there. I'd apply for a job
at quantum Biology.

Speaker 1 (05:07):
Depends on which quanta they use to pay you, I suppose.

Speaker 2 (05:09):
Y Oh, no, that's true. And then how good their
late station is?

Speaker 1 (05:15):
Is that you decide a job to take?

Speaker 2 (05:17):
Well, you know, I guess I'm not employed by anyone
right now, but that would help. That would help. And
if they'll do my laundry, that would be great.

Speaker 1 (05:27):
Aren't you self employed?

Speaker 2 (05:28):
Oh yeah, I guess that counts, So.

Speaker 1 (05:30):
You should ask yourself for a late station.

Speaker 2 (05:32):
I make a pretty mean latte. I take good care
of myself.

Speaker 1 (05:36):
There you go, and you do your own laundry, right,
So the boss is really providing over there on the
science farm.

Speaker 2 (05:41):
Mmm, you make a good point. Yeah, we do do
our own laundry around here, but we're the bosses, all right.
Point made.

Speaker 1 (05:49):
But we're not here to talk about laundry and coffee today.
We're here to dig into biological processes and to ask
whether there is a quantum nature to it, whether the
quantum description of the universe, the quantum nature of reality
reveals itself somehow in biology if you can find place
in biology where quantum mechanics is necessary to make things

(06:11):
work or to understand them.

Speaker 2 (06:13):
And our usual place to go to to get our
conversations started is the clever listeners of DJEU. Should we
check in with them first?

Speaker 1 (06:20):
Absolutely, let's do that. Thanks very much everybody who volunteers
to answer these weird questions that you get asked without
any chance to prepare. We love hearing your voice and
your thoughts, and we love if you've participated. We are
talking to you. That's right, you've been listening for years
without participating. But you know you want to please write
to me two questions at Danielandjorge dot com. So before

(06:44):
you hear these answers, think about it for yourself for
a minute. What is quantum biology? Here's what people had
to say.

Speaker 4 (06:51):
Quantum biology is a study of microscopic life and how
such live influences and influenced by quantum effects. For example,
I'm pretty sure microtubules and specific cells are believed to
exhibit potential quantum behavior.

Speaker 3 (07:06):
Well, it's definitely a super cool sounding term. Maybe it's
applying the nondeterministic nature of quantum mechanics to biology. I'm
thinking about like hydrothermal vents and quantum randomness helping to
generate early DNA and early life.

Speaker 5 (07:26):
So quantum biology, I guess, would be looking to see
within the human body or other animals to see if
there's some weird quantum effects going on, or if our
body somehow uses quantum mechanics in a way. So perhaps
our senses or organs or our brain does something really weird,

(07:47):
like where it communicates information really fast in an impossible way,
and so we're thinking that maybe there's some quantum phenomenon
going on.

Speaker 6 (07:57):
If we're not talking about ant man in the quantum realm,
then I think I've heard something about this with bees
and their ability to see on ultraviolet, something quantum effects
with flowers and vision.

Speaker 7 (08:11):
I do know what biology is. I kind of know
what quantum is. Maybe quantum biology helps explain quantum phenomena
that happens in biology, maybe something like bioluminescence, or maybe
something with like how energy is transferred a photosynthesis. So
maybe there's some quantum phenomena that can help explain biological processes.

Speaker 1 (08:34):
What is quantum biology? I don't know.

Speaker 8 (08:38):
I would guess quantum biology is the study of the
crossover of quantum physics and biology. I kind of recall
hearing a couple of years ago that we discovered that
birds are able to tap into some quantum process and
use that for navigation, and so I would guess maybe
it's something similar along those lines of different types of
biological creatures and how they are able to utilize quantum physics.

Speaker 2 (09:03):
So those were some really great answers, and for me,
they sparked some old memories, Like I feel like I
had heard something about quantum processes and bird navigation, which
you know, tie together my interest in animal behavior with
quantum stuff. And it made me wonder, does something like
cancer like caused by mutations from UV radiation is that?

(09:25):
Does that count as quantum biology? So what are we
What is the scope that we're talking about here? In particular?

Speaker 1 (09:31):
I see what you're doing. You're gonna say quantum mechanics
kills people, right, You're going to try to make us
look bad.

Speaker 2 (09:37):
What is it? It's my turn to be the one
who who delivers the bad news. I think your evil
laugh is better, but I'll work on it.

Speaker 1 (09:47):
That was a good Quantum Wizard cackle. I liked it, thanks,
But yeah, that's exactly what we're going to try to
do today is trying to understand where quantum mechanics affects biology.
And that's really what quantum biology is is the understand
of the impact of quantum mechanics, the rules of quantum mechanics,
and how they filter up to the big stuff, the
sloshy stuff, the goopy stuff that we love in biology.

Speaker 2 (10:09):
So I'll be interested in seeing if understanding quantum mechanics
mostly helps us understand when things go wrong, or if
it also helps us understand like helpful things like navigation.
Is it just does it kill you when it messes up?
Or can it be helpful?

Speaker 1 (10:23):
Yeah, I'd be fascinating If you need it's like quantum
mechanics in order to enjoy sex or something like that, that
would be cool. That'd be a good selling point for
quantum mechanics.

Speaker 2 (10:30):
I would definitely care then. Yeah, I'd buy that book.

Speaker 1 (10:35):
All right. So let's start off by reminding ourselves what
the rules of the quantum realm are. What are we
talking about here? Because we understand that physics tells us
about how things move and fall and inertia and motion
and gravity and all that stuff. But that's the kind
of stuff we already find intuitive. We know that dolphins
know the rules of fluid mechanics, and that birds understand

(10:56):
how to fly, and of course they have to follow
the laws of physics. But that's classical physics. That's the
physics that we grew up with, the physics that we
have an intuition for. The physics that defines why a
ball flies through the air into your glove, or why
a car crashes or doesn't crash. What we need to
understand today are the rules of the quantum realm, which
seem fundamentally different the physics basically of the tiny particles

(11:19):
instead of the big stuff.

Speaker 2 (11:20):
So does that rule out cancer caused by solar radiation?

Speaker 1 (11:25):
No, it does not, absolutely. Okay, as long as we
can find a quantum link, then we can blame quantum
mechanics for all of cancer. Don't worry, we'll get there.

Speaker 2 (11:32):
Oh that's great, Okay, great, I look forward to it.

Speaker 1 (11:35):
Let's do a quick review on what is the nature
of the quantum realm? What are we talking about here?
What are the rules of quantum mechanics that could influence
biology in a weird, sort of unusual, non classical way.
And point number one is that quantum mechanics has an uncertainty.
And this is often described as like Eisenberg uncertainty principle,
there's fuzziness to the universe. But it's much more than that.

(11:59):
It's much deeper than just like we don't know where
that electron is. Philosophically, it requires a complete revision of
your understanding of what location means, like in the sort
of Bill Clinton sense, like what is means when we
say where the electron is?

Speaker 2 (12:17):
This is one of the raunchier shows we've done in
a while.

Speaker 1 (12:22):
Okay, all right, yeah, I'm trying to keep it sexy
in this case. What I mean is that's more than
we don't know where the electron is. It that the
electron doesn't have a location at every point. Like when
you think about a baseball flying through your backyard, it's
very natural to think that it has a location at
every point in time. And like freshman students of physics

(12:43):
learned to write the trajectory as a function X of t,
which tells you where it is at every point in time.
Because we assume that objects exist somewhere at every point
and that they have a smooth path. They don't like
disappear from here and just appear over there. It's like
a very basic assumption of the way the world works.
But that's not true for electrons. Electrons have locations at

(13:06):
moments like snapshots. It's here at this time, it's there
at that time, But they don't have paths. They don't
have to go from here to there. Even if they
can be here and then later be there, you don't
have to connect them. In fact, you can't connect them
with a smooth path.

Speaker 2 (13:23):
I guess as an animal behaviorist, I was hoping that
that uncertainty sort of provides an at like if you
average it, you get an answer that tells you everything
you need to know, so you can ignore it. But
we'll see if that's true.

Speaker 1 (13:34):
Yes, exactly. That seems to happen when you have lots
of electrons. When you're averaging over many, many particles, then
things seem to come together and behave differently. Like you
have an individual electron, it doesn't have a path. But
if you have ten to twenty nine particles and exists
in a baseball that does have a path. And so
the weird thing about quantum mechanics is that when you
zoom out, when you aggregate it over many many particles,

(13:56):
different rules emerge. And that's the mystery of the universe
we were talking about earlier, like, we don't really know
why stuff does emerge. Why when you zoom out the
rules seem to be different. Why can you write simple
mathematical stories about the motion of a baseball without really
understanding what it's made out of and what the rules
are for what it's made out of. It's this incredible
magic trick we do that allows us to do science

(14:18):
at so many different levels without understanding the internals. Agreed,
But we definitely learned that electrons don't have this property.
They don't have a path or trajectory. They have multiple possibilities,
and they can maintain those possibilities simultaneously. Like if an
electron interacts with something, it might go left or might
go right, for example, when it hits a magnetic field,

(14:40):
and the universe allows it to have those possibilities simultaneously,
to say, well, maybe you went left, maybe you went right.
We don't know both of them are possible. You sometimes
hear this set is like, oh, the electron is in
two places at once. That makes it sound like, oh,
it's got path, it's just got more than one of them.
But the reality is that doesn't have a path two

(15:00):
probabilities of being in those places, which it can maintain
simultaneously without actually being in either one.

Speaker 2 (15:07):
So I am assuming we'll get to the electron transport chain.
I'm feeling amazed that stuff like this works when you
can't depend on your partner the electron, to do their part.

Speaker 1 (15:19):
Yeah, it's amazing to me that anybody relies on electrons
to do anything. They don't seem very cooperative. The second
crucial element you have to understand about quantum mechanics to
think about its impact on biology is that randomness. Like,
if an electron can interact with a magnetic field, it
has a probability to do one thing and a probability
to do something else. That's very quantum mechanical. But then

(15:42):
sometimes we make a measurement. We say, well, I want
to know is the electron over here or is it
over there? So we interact with it with like an
eyeball or something big and classical. It forces the universe
to make a choice, is the electron over here or
is it over there? And we want one of those
snapshots to collapse those probabilities. Something incredible happens in that moment,

(16:02):
something which we never otherwise experience true actual randomness. We
think we experience randomness in the universe a lot, like
when you roll a die, or you flip a coin,
or they pull lottery numbers. But that's not actual randomness.
That's just chaos. That's just something which is complicated and
hard to predict. But if you repeated it the same way,

(16:24):
exactly the same way, twice, you would get the same answer.
Chaos is when things are very sensitive to exactly how
you've done them. Randomness means if you do things exactly
the same way twice, you get different outcomes.

Speaker 2 (16:38):
So I'm finding myself realizing that I'm not one hundred
percent clear on the difference between randomness and uncertainty. Does
the randomness generate uncertainty?

Speaker 1 (16:49):
Yeah, absolutely, It works sort of both ways. The randomness
generates an uncertainty, but the uncertainty allows for randomness. The
uncertainty says, oh, there's several possible outcomes for the electron,
and then the universe comes and it picks one. How
does that happen If the electron has a fifty percent
chance of being left and fifty percent chance of being right,
somehow the universe decides, Oh, this electron's left or this

(17:11):
electron's right. We don't know what the mechanism is for that.
We don't have any way to do that ourselves. Like
if you came into being said Daniel, build me a
device which will generate random outcomes left or right ones
or zeros, I couldn't do it unless I connected myself
somehow to a truly random quantum process, Like I couldn't

(17:31):
build a random number generator on a computer. You probably
have one on your computer, but it's not actually a
random number generator. You run it twice the same way,
it will generate exactly the same series twice. The only
way we have to generate randomness in the universe is
to connect to quantum mechanical processes. Cosmic rays and electrons

(17:51):
and anything tiny and quantum can actually be random.

Speaker 2 (17:55):
And so we do have random generators using quantum processes.
And can you give an example of like a process
that requires that actual kind of randomness as opposed to
you know, the random number generators I can get on Google.

Speaker 1 (18:08):
Most things don't need real quantum randomness. Most things are
fine with what we call pseudo orandom number generators that
approximate randomness. And so for most applications, like you're running
a simulation or something, you can do just fine with
pseudo random number generators. You can create real random number
generators if, for example, you have like a camera quointed

(18:30):
at a cosmic ray detector. Cosmic rays are quantum particles
and they are truly random, and if you use that
as like a seed, then you can generate actual random numbers.
But there are very are few things that really need
true randomness.

Speaker 2 (18:43):
That's good because I use the Google random number generator
a lot.

Speaker 1 (18:47):
Yeah, it's fine, exactly, it's fine.

Speaker 2 (18:50):
Okay, all right, so we got uncertainty and randomness. Is
there anything else we need to know about quantum mechanics
before we move on?

Speaker 1 (18:57):
Well, the word quantum means something important. Quantum means like
a unit, a discrete chunk, and that tells us something
about how the world works. Quantum mechanics gives us a
picture of the universe that's not smooth and infinitely divisible,
but built out of discrete packets. And that's a little weird.
It's not something we're used to. Like. If you imagine
talking to your friend or cackling loudly, right, you can

(19:20):
cackle loudly or you can cackle quietly, and you can
make that cackle quieter and quieter, and it feels like
you could keep making that quieter forever, like keep making
it half as loud and half as loud and half
as loud, and you could just keep going forever. Right,
there's no minimum loudness.

Speaker 2 (19:35):
Okay, sounds like it would get annoying pretty quick.

Speaker 1 (19:39):
It's like that song, right, a little bit quieter now,
a little bit softer now, but.

Speaker 2 (19:44):
It doesn't go on forever, and that's what you enjoy it.

Speaker 1 (19:46):
Yeah, exactly. If it went on forever, it would be annoying.
But you can't do that with things like a light beam.
A light beam seems like it's continuous. It seems like
you could dial it up to really bright or really dim,
and that you could keep making it dimmer and dimmer
and dimmer forever. But the truth is you can't because
that light beam is made of quantum objects, individual packets

(20:06):
of light photons, and so there is a minimum brightness
you dial your laser down, so it's emitting one photon
at a time. That's the minimum brightness. You can't go
to half a photon, or a quarter of a photon,
or an eighth of a photon.

Speaker 2 (20:20):
So a photon is something we don't expect that will
ever break down in more detail ever.

Speaker 1 (20:26):
Yeah, that's a good question. Is a photon fundamental or
is it made of other stuff? As far as we know,
it's a ripple and a quantum field that is itself fundamental.
It can't be broken into smaller bits. But even if
it could, it wouldn't be a photon anymore.

Speaker 5 (20:39):
So.

Speaker 1 (20:39):
Still, photons are the discrete unit of light. You can't
break them any smaller.

Speaker 2 (20:44):
So electrons are made up of smaller parts, but when
you take those parts out, it's not an electron anymore.
So electrons are also fundamental parts, is that right?

Speaker 1 (20:53):
Yeah, we don't know if electrons are made of smaller
bits or not. Protons certainly are electrons. We don't know.
We suspect probably they are. We don't know what's inside them,
but yeah, if you took them apart, it wouldn't be
an electron anymore. The same way like if you take
a car part. It's not a car anymore.

Speaker 2 (21:06):
It's just a bunch of parts, got it all right?

Speaker 1 (21:08):
So the incredible thing is that these are the rules
of the quantum realm. They describe how tiny particles interact,
and how they move through the universe, or how they
don't move through the universe because they don't go at all,
how they exist and froth and fluctuate. And we think
that the whole universe is made of these pieces. These
are like the fundamental legos of the universe. They follow
these rules. But when you put enough of these legos together,

(21:31):
something weird happens. Right, different rules seem to emerge. You
put a lot of these particles together, as we were
saying earlier, then you can start to use classical physics
to describe it. Baseballs don't have any real randomness. Sound
waves can be made softer and softer and softer. And
so we have the rules of the quantum realm, and
then we have the rules of sort of our realm,

(21:51):
and we don't really know how these are connected.

Speaker 2 (21:54):
So I am yet again feeling the impulse to say,
doesn't this mean that we could just I've reached out
the quantum stuff and we don't need to go there.

Speaker 1 (22:03):
Most of the time we can, and that's why it
took us so long to figure out quantum mechanics, because
in our world it's not obvious. We can mostly ignore
the quantum nature of our world, or we would have
seen it much earlier. Right. It took into like the
discovery of radioactivity, which triggered a whole revolution in the
way we think about the world, and the atom and
discovery of all those particles one hundred years ago, and

(22:25):
the photoelectric effect for us to see cracks in the
classical world. So it's very, very subtle, and most of
the time we can ignore it, and you biologists can
pretend quantum mechanics is not even a thing. Yes, But
that's the question of today's episode, is are there cracks
like that in biology where the world reveals its true nature?

Speaker 2 (22:44):
Do you have a sense for when we started asking
questions like this, When did we start understanding quantum mechanics
and when is the earliest instance where people tried to
like meld it with biology.

Speaker 1 (22:55):
Quantum mechanics and its foundational ideas. Day two about like
nineteen hundred. It was Albert Einstein who came up with
the idea that light came in these little packets. We
have a whole episode about how the photon was discovered
from the photoelectric effect. Basically, you shine bright lights on
metal and it will boil off electrons. And how many
electrons you get and the energy that they have tells

(23:15):
you a lot about how energy is transferred from the
light beam to the metal. And it reveals actually that
the light is made of these little packets because electrons
can only absorb one packet at a time, and how
that filters into biology is a fascinating question. I think
only in the last few decades have people been able
to make these connections between quantum mechanics and biology. Though

(23:37):
I think there's been a lot of woo, you know,
a lot of like, hm, we don't understand the brain
where is free will wait? Maybe quantum mechanics fills in
that gap. So I think in terms of solid science,
we'll dig into a bunch of examples, but I think
it's just a few decades old.

Speaker 2 (23:52):
Oh man, that's truly. You know, on your nspgrades you're
supposed to say you're interdisciplinary, but usually the answer is like, well,
I do two different kinds of neurochemistry. But this seems
to really fit the bill. So all right, that's been
a lot to absorb, my friends, Let's take a commercial
break and then we'll get some examples. All right, so

(24:23):
we are now caught up on quantum mechanics. Surely we
know everything there is to know about quantum.

Speaker 1 (24:29):
Mechanics now, it only takes like fifteen minutes, right, and
then boom, you're a quantum mechanic.

Speaker 2 (24:34):
Yeap, easy pasy. But biology is the hard stuff. So
so now let's dig into biology. Can we start with
some examples where quantum mechanics helps us understand biology better?

Speaker 1 (24:45):
Yeah? Absolutely, let's dig in because in the end, we're
all made of these quantum objects, and surely at some
points their quantum nature must be important. Right. So one
of my favorites is exactly the idea you mentioned earlier,
which is electron transport chain. Maybe you should give us
a little summary about what an electron transport chain is.

Speaker 2 (25:05):
I have purposefully not thought about the electron transport chain
since I was a freshman undergrad, and I've never had
to teach an intro biology class, so I've never had
to go over it again. So how about you tell
us about the electron transport chain.

Speaker 1 (25:22):
Well, I have recently had to review this because my
daughter is a freshman in high school and she's taken biology,
and she prefers to ask me these questions rather than
my wife, who was a PhD in biochemistry, because when
she asks my wife, she gets what my daughter calls
a college lecture about it. And when she asks me,
it's a very short answer because I don't understand it

(25:43):
very well. So here goes. Electron transport chains are part
of basically how we transfer energy. You eat food, it
goes into your stomach. How does that energy get converted
into a useful form for your body to take advantage of. Well,
there's a whole series of reactions there. This oxid, there's reduction.
All those things are part of converting your nutrients into

(26:05):
basically sugars that other parts of your body can use.
And how do these chemical reactions happen? Like, why do
they happen? They happen because they're energetically favorable. Stuff bumps
into other stuff and it finds that it can click
together and then doing so release some energy. In this case,
the energy that's released are electrons moving around. Basically electrons
are sliding down energy gradients. It's like you're building a

(26:28):
snowy hill for the electron and it just wants to
coaston down to the bottom. So these electron transport chains
are molecules passing electrons from one to the other in
order to release some energy and release it into some
storage unit, some atp or some other kind of sugar
that the body can later use.

Speaker 2 (26:48):
Your slitting example sounds so fun. I'm imagining all the
electrons in my cells right now going and I feel
so much better about the energy I'm using.

Speaker 1 (26:58):
And so mostly this is fairly straightform, and the sledding
example works because things just slide downhill. But sometimes there's
a barrier, like sometimes the electron is trapped in a
little valley and it would love to get over a
hill down to the next deeper valley where it has
lower energy, but it can't get over the hump. Right,
It's like trapped in a valley. And so if the
electron was purely a classical object like a kid on

(27:20):
a sled, and they weren't going fast enough to go
over that hill, then they'd be trapped there forever. Right,
If you don't have the speed to go over that hill.
You just can't go over that hill because classical objects
have to go places. If you're here and then you're there,
you have to go from here to there. There has
to be like a continuous chain of locations between here

(27:41):
and there for you to exist in. And if you
don't have the energy to get to some of those locations, boom,
you're trapped. Right. That's why people can get stuck in
a valley if you don't have like speed to get
over the hill.

Speaker 2 (27:51):
So I'm having trouble connecting that example to like the biology.
So are you essentially saying that like it had to
be quantum particle that did this because biology absolutely required
quantum tunneling to be able to make all of this work,
because there are hills going down the electron transport chain

(28:12):
that we couldn't get over otherwise.

Speaker 1 (28:15):
Yes, that's exactly right. The electron transport chain is not
just a smooth hill. There are some barriers there, and
in order for the electrons to get from the top
to the bottom, they have to get over those barriers.
But they don't have enough energy to get over those barriers.
But they can do their quantum magic, right. Quantum particles
don't have to go over barriers. Quantum particles can be

(28:36):
on one side of a barrier, and then later they
can be on the other side of a barrier without
ever going through the barrier. If you have a probability
of being here and a probability of being there, you
can be here now and be there later without going
from here to there. So this is the process we
call quantum tunneling. If an electron didn't have this capability,

(28:56):
if it was a classical object, then it couldn't get
over these barriers. And again we're using the barriers and
the sledding example as a way to visualize like the
chemical reactions the energy ingredients that are involved in this
electron transport chain. Getting the energy from the nutrients into
your sugar as a whole series of chemical reactions that
involve like sliding down these energy gredients. But there are

(29:18):
bumps in this energy ingredients, and the electrons have to
quantum tunnel through those bumps, through those barriers, or the
whole thing wouldn't work.

Speaker 2 (29:26):
Wow, Okay, And so there's a bunch of randomness and
there's a bunch of uncertainty. Is it surprising that the
electron transport chain works as well as it does, like
that they don't quantum tunnel their way out of the
transport chain or something.

Speaker 1 (29:41):
Yeah, that's a really cool question. The concept that there's
uncertainty and randomness makes it seem like it's out of control,
like it's unpredictable, right, But remember that quantum mechanics does
make very firm predictions. It's just that it predicts the probabilities.
It doesn't predict the exact outcome because there's real randomness,
but it's very firm on what the possible outcomes are.

(30:02):
So it doesn't say like, oh, the electron can just
do anything at once. It's not like there's no rules
at all and anything goes. This isn't like a rave, right,
There are still rules, and the quantum mechanics tells us
the electron can be here or it can be there.
It can't just like go willy nilly and join some
other party. And so it still determines what happens. And
if you average over many electrons, you can very very

(30:23):
accurately predict what's going to happen. And since there are
lots of molecules and lots of electrons involved, then even
if you can't predict an individual electron, you can still
rely on the processes happening at a reliable level.

Speaker 2 (30:37):
That's kind of amazing that that system evolved.

Speaker 1 (30:40):
It is sort of amazing. And it relies on the
quantum nature of the electron. Like, you could not build
this system out of tiny little balls of stuff that
move the way baseball do. So the quantum nature of
the electrone is crucial to the electron transport chain, which
is really fundamentally like our entire power chain. Based on
my understanding of ninth grade BIOLGCE.

Speaker 2 (31:00):
Now, so here's the thing. Biologists have to take physics classes,
and it really seems to me like they should start
the lectures for you know, physics for biology majors by saying, look,
the electron transport chain couldn't happen without wantum mechanics. Yeah,
and then we'd pay attention.

Speaker 1 (31:21):
You're saying, intro science could be taught in a more
compelling and fascinating way without turning off masses of people.

Speaker 2 (31:28):
What really, unless it's the classes taught by my friends,
who I'm sure are all doing it the best possible way, I.

Speaker 1 (31:38):
Do think it's really fascinating. A lot of this stuff
is often brushed over because also there's just so much
to learn, Like when you're learning about the electron transport chain,
there's so many details. Their biology is so complicated already,
you know, so many interactions, so many pieces. It's amazing
to me that it ever works. You know, it's like
a huge Rube Goldberg machine designed by a crazy person.

Speaker 2 (31:59):
Yeah, Goldberg machines are already kind of wild, but yes,
one that's made by a crazy person would be even
more wild. So okay, so are most of the examples
things like intro biology or like molecular biology stuff. I
guess we haven't gotten to my pet topic yet.

Speaker 1 (32:17):
We're going to get there. We're going to get to
neurons and brains.

Speaker 2 (32:19):
Okay, okay, all right, so what's next?

Speaker 7 (32:21):
Then?

Speaker 1 (32:21):
On the top of energy transport are photons, Right like plants,
for example, they don't eat peanut butter sandwiches and need
to digest them the same way we do. They have
a different process. So interacting with light opens lots of
questions about the quantum nature of light, like how does
photosynthesis all work? How do we absorb that energy? And
then even for humans, light is something we rely on

(32:42):
to build our picture of the world. Does it matter
that it's made of individual photons? Could we see individual photons?
To me, that's a really fascinating question, like whether we're
able to interact with a quantum object, the experience a
quantum object, like a single photon hitting your eyeball. Did
you even see that?

Speaker 7 (33:01):
Ooh?

Speaker 2 (33:01):
And you know plants sometimes turn in the direction of light.
Could they turn in the direction of a single photon?

Speaker 1 (33:07):
Yeah? Right, really fascinating. I think about this a lot
when I'm looking up at the night sky and you're
looking at some really dim star, some star you're just
barely able to make out, and imagine being really close
to that star. It's an enormous furnace. It's pumping out,
like huge numbers of photons out into the universe. If
you're very close to it, then your eyeball is going
to get roasted. You're inundated with photons. As you get

(33:29):
further and further away, those photons spread out more and more,
and now you're like between photons, and so the number
of photons hitting your eyeball is dropping. And now if
you're millions or billions of light years away, you're so
far away that most of the photons are not going
to hit your eyeball, but one of them might. So
to me, a really interesting question is, like, how many
photons do you need to see from a star to

(33:52):
see that it's there? What's the minimum number you need?

Speaker 2 (33:55):
Do we know?

Speaker 1 (33:56):
We actually have done this study. It's really fascinating. People
have been wondering, like can the human eyeball see an
individual photon? If you fire a single photon at the eyeball,
will somebody experience a flash in the dark? Or do
you need like five or ten or five million photons?
So people have been trying to do this experiment for decades.

(34:17):
It's really hard because number one, you need to be
able to generate single photons, which is not something that's
easy to do experimentally. And number two, you need to
know that a photon was generated. Like if somebody's sitting
there with the clicker and they're going to press a
button when they see a photon, you need to be
able to correlate that with like an actual photon hitting
their eye. But photons are tricky, right, Like you can't

(34:39):
see a photon from the side. You can only see
a photon, but it hits your eyeball, So like a
little glowing packet. Right, So this is something that was
really tricky to do. They're only really just able to
investigate conclusively a few years ago.

Speaker 2 (34:52):
What was the piece of technology that opened up that question,
like better lasers or something. It's always better lasers, Probably
not better lasers this time, so.

Speaker 1 (35:02):
It was fancy optics, right. So essentially, what you do
is you take a light source and you crank it
down until it's shooting out just a few photons at once.
But again, you got to know when the photons are
being shot out, so you can ask like, are you
seeing real photons? Are you just randomly clicking the button?
In order to know when a photon arrives. What they
do is they use this cranzy piece of optics that

(35:24):
splits a photon. So you take a photon and it
hits a special crystal call a down converter, and what
it does is it splits each photon into two photons
that have half as much energy, and so one you
can use to tell, oh, the photon was here, and
the other one you can send to your subject's eyeball.

Speaker 2 (35:42):
So does that mean they're only detecting half a photon?

Speaker 6 (35:47):
All?

Speaker 1 (35:47):
Awesome? Question. They're still detecting one photon, it's just lower energy.
So if you want to send people like a green photon,
then you need to produce photons that have twice as
much energy as a green photon, and then split it
into two green photons, send one to the eyeball and
the other one to your recording device that tells you
when the photon was made. Because anything that's emitting individual photons,

(36:10):
those are quantum objects that they're going to be random.
You can't control when they're made. We have to record
when you made one.

Speaker 2 (36:16):
And then you have to hope that your observer doesn't
blink at.

Speaker 1 (36:18):
The right exactly. So in twenty sixteen, they did these
experiments with humans in dark basements shooting green photons at
their eyeballs, and those folks got it right. They were
able to like press the button at the right time
to indicate that they saw individual photons hitting their eyeballs,
which to me is kind of amazing.

Speaker 2 (36:38):
I guess one photon is all you need to activate
a rot or a cone.

Speaker 1 (36:41):
Yes, those rods and cones have these proteins in them
which are very very sensitive, and they change configurations when
they absorb a single photon.

Speaker 2 (36:48):
Absolutely, Are we unique? It's so nice to think we're unique.
Or are we the only ones who can view just
one photon?

Speaker 1 (36:56):
Definitely not. We've seen this actually in frogs earlier, and
it's easy to do in frogs because you can just
like take their eyes and put like voltage clamps on
the optic nerve behind the eyeball and you don't have
to worry so much about them. You can't do that
kind of stuff for humans, so it's more complicated. But
frogs can definitely see single photons, and I suspect lots
of animals have more powerful eyes than we do. Eagles

(37:16):
probably can definitely see single photons.

Speaker 2 (37:19):
But would they need to see in an environment that dark?
They're not usually hunting that dark.

Speaker 1 (37:24):
That's true. Maybe owls, then maybe owls can see there photons. Yeah,
And so that's interacting with a quantum object, right, And
that opens the door to a really interesting philosophical question
about experiencing a quantum object.

Speaker 2 (37:38):
You've just told me that we can experience a quantum
object by seeing one photon hit or eye. So what
do you have in mind that's different.

Speaker 1 (37:46):
I'm wondering if we can experience its quantum nature like.
Something that's really interesting about a photon is that it
can have this superposition of two possibilities. Say, for example,
you produce this photon in a way that's not clear
whether it's going to go into your left eye or
your right eye. It is a fifty percent chance of
going in either one. According to quantum mechanics, it can
maintain both those possibilities, right, as long as it doesn't

(38:09):
interact with a classical object that collapses its wave function,
it can maintain both possibilities. So imagine now you're doing
the same experiment, but you're not sure which eyeball it's
going to hit. If you're interacting with a quantum object,
is it possible to like experience both branches of the
wave function, to see it simultaneously in both eyes. What

(38:32):
would that be like subjectively to experience something with its uncertainty?
Or does our eyeball just like collapse the wave function
and we experience it and left or the right. If
you're interacting with a quantum object, it opens the door
to this possibility of like experiencing its quantum nature.

Speaker 2 (38:48):
So my brain is trying to catch up. My guess
would be that it collapses when it hits the eye. Yeah,
but what's the answer do we know?

Speaker 1 (38:58):
We don't know. This is not an experiment we've been
able to do, right. It's much more complicated than the
initial experiment because now you have to prepare a photon
and have it be in this quantum superposition using like
some half silver mirror whatever. And you know, the classical
theory quantum mechanics agrees with you. It says, look, the
eyeball is a big classical object. It's going to collapse
away function. You're going to see it in one eye

(39:18):
or the other eye. But there are alternative theories of
quantum mechanics that say, you know, the collapse happens sort
of spontaneously depending on the size of the object you're
interacting with, so like differently sized parts of the eye
might have different rates of inducing the collapse. I don't know.
It's kind of bonkers, but it's a really fun edge
of quantum biology for me, trying to get things to

(39:39):
experience their quantum nature. I wonder if our brains are
even prepared for that.

Speaker 2 (39:43):
Mine's not. I mean, it seems to me that what
it interacts with the rods or the cones, that that
should collapse it. But I don't know.

Speaker 1 (39:54):
I don't know because rods and cones are just made
of quantum objects. Right at the edge of the rods
and cones are quantum some particles bound into molecules. Why
should that collapse? The wave function? That never made any
sense to me. And orthodox quantum mechanics says you put
enough quantum objects together becomes a classical object. What does
that really mean? How many quantum objects do you need
to put together before it becomes classical? None of those

(40:16):
questions have answers.

Speaker 2 (40:18):
Wow, okay, well, my brain needs a little brain break,
So how about we take a commercial break and then
we'll move on to magneto reception. Another example. All right,

(40:46):
my brain is back to full capacity. I'm ready to rock, Daniel,
let's give me another example. We're gonna be talking about
magneto reception, and I feel like this is probably when
we start talking about birds and migration. Maybe, yes, yes, exactly,
All right, let's do it.

Speaker 1 (41:03):
One of the things I love thinking about in terms
of quantum mechanics and biology is what it's like to
experience the world differently, like if we had different senses.
We build this picture of the world from our vision
and our taste and our touch and our smell. But
there are other animals out there that experience the world differently.
They have like different senses that we just don't even experience.

(41:24):
And trying to imagine, like what is it like to
have another sense. It's like trying to imagine what it's
like to hear if you're deaf, or what it's like
to see something if you're blind. It feels like it's
going to be impossible to capture. And there are animals
out there that have senses that we don't have. For example,
we know now that birds, when they migrate across the world,
part of the way they find their way is by

(41:46):
sensing the Earth's magnetic field. Like this is something they
can experience internally. They don't like little machines on their
wrists with an arrow that they can look at with
their eyeballs. They can innately sense the magnetic field of
the earth.

Speaker 2 (42:00):
You know, most of the time biology makes me feel
just incredible joy, But this stuff really bums me out because,
like I was reading Edyong's I think it's called this
Immense World, and it's all about animal umweltz and like
the different ways they sense the world, and you know,
like there are colors we don't see, there are flowers

(42:20):
that are even more beautiful than we can appreciate, and
the insects can see but we can't. And the idea
that you know, there's magnetic fields that I could see
but I'm missing it. It's amazing, but also I'm bummed
out that I don't get to appreciate these extra colors
and these magnetic fields. And anyway, okay, let's keep moving on.

Speaker 1 (42:38):
You know, I read that book as well, and I
loved it for all the science of the ways that
the animals sense the world, But I wish that he
had dug deeper into that question, like what is it
like to experience a magnetic field? What is it like
to see the world if you're a sea scallop or
a spider with two different kinds of eyes, or to
think about the world if you're an octopus with different

(42:58):
kinds of brains partially distributed across your body. Maybe that's
more philosophical than he wanted to get. But I wish
he hadug deeper into that question.

Speaker 2 (43:06):
I think there's maybe no way for us to know
yeah it without getting too philosophical.

Speaker 1 (43:11):
What is it like to be about Nobody knows.

Speaker 2 (43:13):
I mean, because he was saying, like, you know, are
there apps that you could make so you could see
the flowers but you could detect like, Okay, there's a
pattern here that we can't see. But if there's a
color we can't see, no app could bring that color
to life in a way that our eyes could pick
up on.

Speaker 1 (43:28):
Yeah, that's right, because the color is an experience in
your brain. It's generated in your mind. Right, The photons
are not red or green, or blue or purple, they're
just different energies in your brain creates that experience. Anyway,
back to birds and their bird brains. Birds in their
eyeballs have these weird proteins, and the proteins have electrons

(43:48):
in them that have opposite quantum spin. Quantum spin is
a property eve an electron. It's sort of similar to
spin mathematically and even physically. It's similar because it's a
kind of angular momentum, but it's also very very weird.
It's not like electrons are physically literally spinning little balls.
It's some other weird kind of spin that we call

(44:10):
quantum spin. But you can think of it like electrons
can either be spin up or spin down, and these
protons have these pairs of electrons, and sometimes these electrons
like to flip, like they're up and they're down, they're
up and they're down. And the rate at which they flip,
and how often they're aligned with each other or not aligned,
like are they pointing the same direction or are they
pointing opposite direction depends on how strong the magnetic field is.

(44:34):
So if you have a stronger magnetic field, the rate
at which these electrons flip their spin changes. So if
you're like watching these electrons, you can sense and you
can measure the strength of the magnetic field around you
by looking at how fast the electrons spin is flipping.

Speaker 2 (44:51):
Is this specifically happening in their eyes or m hmm.

Speaker 1 (44:55):
There's a special kind of protein in their eye which
is triggered by light weirdly to have this property. It's
like energized by light to get into this state where
they can then sense the magnetic field. But then it
sends that information along a different neural pathway, so we
don't really know, like what is it like to be
a bird. They're definitely getting this information, we don't know

(45:16):
if they're literally seeing magnetic fields like when they look
out on the world, is this part of their visual
experience or if it's an overlay on top of their
mental image the way like smell is or sound is
for you. It doesn't augment your vision. It's like another
dimension of experience. But we know they can definitely sense
these magnetic fields directly, and it relies on the quantum

(45:39):
properties of these electrons and the way they respond to
magnetic fields.

Speaker 2 (45:43):
Oh man, it's so fun to think about what that
might be like to be responding to magnetic fields.

Speaker 1 (45:48):
What is it like to see this in the universe? Right?
Like I want to pick up every random bird and
just interview it, Like, what's it like to be you?

Speaker 3 (45:55):
Man?

Speaker 2 (45:58):
I'm not sure you're gonna get the answers you're looking for.
Are I think a lot of people have spent their
career studying that question, and they're still working on it.

Speaker 1 (46:06):
There are still working on it. But this sense which
evolution is just like stumbled into this mechanism again, relies
on the quantum nature of the electron. Without this quantum
flipping probabilities and reaction to magnetic fields, it wouldn't be possible.

Speaker 2 (46:20):
I thought I had heard that turtles maybe also respond
to magnetic fields. Is that right? Do turtles have the
same system?

Speaker 1 (46:27):
They might? Turtles are pretty awesome, that's true. I know
that fish have another sense that they can sense electric fields,
though I'm not sure if there's a quantum nature to it.
But fish have this like other sense that we don't
even have. You know, they can tell if there's electric fields.
Basically they could like see radio waves.

Speaker 2 (46:44):
Okay, all right, So you have now convinced me that
this is important because we got to animal behavior and
it mattered, even if it depresses me because I don't
understand it. Okay, So what about I had mentioned at
the beginning mutations and how quantum stuff can mess up
our biology. Let's talk a bit more about that. How

(47:05):
important is that?

Speaker 1 (47:06):
Yeah? Exactly. We've been talking about the joy of experiencing
the world in new ways. Let's bring it down and
talk about the cancer but also sex. Right, right, we'll
talk about cancer insects at the same time.

Speaker 2 (47:16):
Okay, it's a little dark, but let's go for it.

Speaker 1 (47:20):
So the universe is raining down particles on us all
the time. The space out there beyond our atmosphere is
not actually empty. It's filled with tiny high energy particles.
We call them cosmic rays. They're just like little protons
or electrons, or sometimes like iron nuclei flying through space.
You can think of them like tiny little quantum meteors
of death. They totally are, and sometimes they smash into

(47:43):
our atmosphere and they cause a little shower the way
like if a rock hits the atmosphere at high speed,
it's going to burn up and create a fireball, right,
same thing happens if a proton hits the atmosphere. It
creates a shower of other particles. Some of those particles
are muons, and the muons will make it all the
way down to the ground and pass through your body.

(48:04):
So right now as you sit there, you're being inundated
with muons from cosmic rays. These are little particles passing
through your body. There's one per square centimeter per minute,
so it's not a huge rate. It's not like neutrinos,
which are everywhere. But these particles are passing through your
body and sometimes they interact with your DNA, that crucial

(48:25):
bit of your biology, damaging or flipping something to change
the encodings and the instructions for life itself.

Speaker 2 (48:32):
You know, I knew that I could depend on you
to get to a point where I would say I
can't let my kid listen to this episode either, because
because then they'll be afraid of just sitting and reading books.
That will be that will be a moment of existential dreads.
So there we are.

Speaker 1 (48:48):
You can't escape this. You can go underground in your bunker,
and you cannot escape muons. Muons can pass all the
way through the earth. We just did a really fun
episode about using muons to like see inside the Egyptian pyramids. Actually,
but muons both cause death and joy. Like muons can
give you cancer because they can change your DNA and
they can make a cell go crazy and start replicating

(49:10):
out of control. Boom, that's your cancer. The same way
that like ultraviolet photons when you sit on the beach
without sunblock can give you skin cancer. Muons can pass
into your body and they can give you cancer. But
they can also sometimes make your kids super smart or
super wonderful. If they hit some DNA in your reproductive system,
the bits that you're going to pass on to your kids,

(49:32):
then they can change the DNA that you're going to
pass on. So if you're like not very fast, they
could like flip a bit and change the encoding, and
your kids can be super duper fast, or super duper smart,
or just super different. And this actually turns out to
be a crucial element of evolution.

Speaker 2 (49:47):
You know, my son is weirdly physically active for our family,
and he's super duper fit.

Speaker 1 (49:53):
M thank you, Muons, Yeah, exactly, Muons, add true quantum
randomness to evolution. Evolution relies on exploring the space of possibilities. Right.
You need diversity, You need lots of different examples, some
of which will survive and some of which will not.
But you only get the ones that survive if you
create them. And so this element of randomness helps evolution

(50:15):
create a big diversity of creators, some of which you're
gonna make it and some of which are not. Really
helps us explore the space of possibilities. And there's real
quantum randomness there, and I think it's crucial to the
reason we're even here.

Speaker 2 (50:27):
Wait a minute, when we talked about the reproductive system,
was that the entire connection to sex? Does it get better?

Speaker 8 (50:32):
No?

Speaker 1 (50:32):
That's it? Sorry?

Speaker 2 (50:33):
Oh what a let down.

Speaker 1 (50:35):
Sorry, I'm not going to give you the secrets to
a quantum orgasm or anything like that.

Speaker 2 (50:38):
That's what I was waiting for.

Speaker 1 (50:42):
That's a billion dollar idea. I'm not just giving it
away on the podcast. Okay, that's from my startup.

Speaker 2 (50:46):
Okay, well, well, and your startup's going to be called
quantum biology through something something, all right, got it?

Speaker 1 (50:55):
But I think maybe the most intimate connection between quantum
mechanics and biology isn't our experience, isn't our decisions. Isn't
the choices we make about how to live our life.
Am I going to work out this morning? Or am
I going to have a donut? Am I going to
take the bus today or drive my car? We seem
to have this experience of free will, we seem to
be able to make these decisions, and decision making in

(51:16):
their brain is very complicated, if not. Something we understand
the brain is this whole set of neurons linked together
in a very complicated, very non linear way. And what
we don't know is if the brain is deterministic but chaotic,
like difficult to describe, difficult to predict because it's so complicated.
The way, for example, if you take a brick out

(51:38):
of a building and it collapses, that collapses, very complicated
to describe, or like hurricanes are difficult to predict even
though they're actually determined by everything that comes before them.
Are the brains like that chaotic, difficult to describe but
actually deterministic? Or is there real randomness in there is
the quantum nature somehow of the bits that make are

(52:00):
neurons generating randomness which leads to like an avalanche, which
affects our decisions.

Speaker 2 (52:06):
Generally surprised by how often physics bleeds into philosophy and
philosophy bleeds into physics. All right, So I like thinking
about free will and how like pests and parasites impact
our free will by like tinkering with our indocrine system.
So you have my attention. Tell me more about how
quantum effects made me decide that this morning was a

(52:28):
smoothie morning and not a big old morning.

Speaker 1 (52:31):
Well, the short answer is we don't know, but we
can speculate about it. And there's people on both sides
of this argument. Some people think, no, it's impossible that
all averages out. The quantum nature of the neuron is irrelevant.
It doesn't matter. You could have built neurons out of
classical objects and they would work the same way. For example,
Roger Penrose famous physicist and Daniel Dennett, famous philosopher of
the mind. They say, quote, most biologists think the quantum

(52:54):
effects all just cancel out in the brain. There's no
reason to think they're harnessed in any way. And the
argument there is like, neurons aren't big, right, you know,
even though they're built out of quantum objects. There's lots
and lots of quantum objects, thousands and millions of these objects,
all acting together, and so even if one of them
has a little quantum fluctuation here or there, it is
going to get averaged out. It's not like an individual

(53:16):
electron moving down the electron transport chain, or a single
muon fluctuating to be here or there to hit you
instead of somebody else. These are big things that are
made of lots of pieces, and so it all just
averages out. That's the sort of conventional wisdom on how
neurons work.

Speaker 2 (53:32):
But there's always someone willing to argue the opposite.

Speaker 1 (53:36):
And we don't know. We don't understand neurons well enough
to say that it's impossible for quantum effects to influence
their outcome. Like neurons are built on avalanches. You have
one which triggers another, which triggers another. It's possible that
a tiny, little avalanche can create a big one. Right.
Scott Aronson, one of my favorite writers on like quantum

(53:56):
computing and philosophy, really a general smart guy, polymath. He said,
brains seem balanced on a knife edge between order and chaos.
Are they as orderly as a pendulum? Are they chaotic
as the weather? We just don't know. And so it's
possible that neuronal networks are sort of balanced right between
order and chaos. That like, they are sensitive to little

(54:19):
quantum fluctuations, but just barely.

Speaker 2 (54:21):
He was at our house the other day, and I
could have talked to him about this.

Speaker 1 (54:24):
You met Scott Aronson.

Speaker 2 (54:25):
Yeah, he's a friend of ours.

Speaker 1 (54:26):
Oh my god, he is so smart. I love his blog.
Every time I'm skeptical about some quantum computing claim, I'm like,
what does Scott have to say? Oh, yeah, it's devastating.

Speaker 2 (54:35):
He yeah, no, he's super smart. But I didn't know
that we could be talking about the nature of free will.
So thank you for fodder for the next time he's over.

Speaker 1 (54:44):
Well, these really are two sort of connected questions, but
also very different. Like, on one hand, we're asking is
there true randomness in the brain, and if there is randomness,
it means that the brain is not deterministic, which means that,
like your predictions of whether you're going to get a
smoothier donut are not determined. And what's unclear is that
whether that actually leaves any opening for free will. Like,

(55:05):
if I tell you, okay, Kelly, you're not just an automaton.
You're not just a mechanical robot that makes decisions based
on what's happened to you and decisions you made previously.
You're a random robot. You make random decisions. Is that
any better? Does that leave you room for free will?
It feels to me like, yeah, there's a gap there,
but it doesn't explain like the subjective experience and how

(55:25):
you're somehow controlling the outcome of physical processes even if
they're random. So I think like randomness and determinism is
separate from the question of free will.

Speaker 2 (55:35):
Yeah, I need a beer, So does the randomness. I
feel like you could sort of predict my behaviors based
on what I've done in the past, which makes me
feel like randomness isn't dictating things, but is it? Just
like randomness is tweaking the path I take a little
bit as I go, and over time it results in
big changes.

Speaker 1 (55:54):
Or yeah, exactly, because sometimes you are on a knife sedge,
like why do you decide to take the bus or
you know those moments of indecision, How do you actually
decide whether to go this way or that way, or
to do this or to do that? And so it
could be very subtly influencing you, not in a way
that you experience or understand.

Speaker 2 (56:12):
Could we study this?

Speaker 1 (56:13):
Yeah, so people are working to try to understand this
by looking at individual neurons, Like let's study the neurons
and see how predictable are they, how sensitive are they
to quantum fluctuations? And then let's study networks of neurons,
like how predictable are their responses if you give them
the same inputs, are you going to always get the
same outputs? Because it might be that this kind of

(56:33):
thing emerges only when you have the combination of quantum
randomness and a chaotic system, Like you need a tiny
little random thing, and then you need a system which
is sensitive to a tiny little difference, you know, like
a butterfly effect, like if you blow a leaf this way,
versus that way, could you set off a hurricane or
prevent a hurricane. You need a system that's sensitive to

(56:54):
a little fluctuation, and then you need those fluctuations at
the right point. So people are doing these experiments, but
they're pretty hard.

Speaker 2 (57:01):
I mean, I can only imagine, like even if you
were just trying to study a simple organism like C. Elegans,
which has you know, only a few handful of neurons,
and we know how they're connected, we know how they develop,
and I can imagine like one corner of the Petri
dish is a little colder than the others, and that
makes it hard to measure quantum effects exactly hard.

Speaker 1 (57:20):
That is the challenge. How do you exactly reproduce two
circumstances so that you know you're getting different outcomes with
the same inputs. There's a whole field of quantum mechanics,
bomy and mechanics. It says it's impossible, and that when
we think we're getting different outcomes on quantum experiments, actually
it's because the initial conditions were slightly different. And so

(57:40):
this is a really big challenge.

Speaker 2 (57:42):
Okay, you have given me loads of material for my
next few rounds of insomnia to think about. Uh, thank
you for that, and I think that's enough for my
brain today.

Speaker 1 (57:54):
I think the takeaway is that we don't really know
if our quantum nature changes the experience of life and
while you're having smoothies and while you're having donuts, but
we do know that we wouldn't be here without quantum mechanics,
without randomness affecting your DNA and the DNA of your ancestors,
without electrons, quantum tunneling through those barriers, all these things

(58:15):
that rely on quantum mechanics, we wouldn't be here. So
in the end, we are all quantum wizards.

Speaker 2 (58:21):
Oh, I like ending on a high note. We're all
quantum wizards.

Speaker 1 (58:25):
That's good exactly. We all have a license to cackle
our way through lives. All right, Thanks very much everybody
for joining us on its quantum journey, and thanks very
much Kelly for indulging in this quantum adventure.

Speaker 2 (58:40):
Thank you for having me. It was a lot of
fun as always.

Speaker 1 (58:42):
All Right. I hope everybody fluctuates into having a very
good week and tune in next time for more science
and curiosity. Come find us on social media, where we
answer questions and post videos We're on Twitter, Discord, Instant
and now TikTok. Thanks for listening and remember that Daniel

(59:03):
and Jorge Explain the Universe is a production of iHeartRadio.
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